Fuel injection nozzle



Oct. 17y w67 E. J. SVOBODA FUEL INJECTION NOZZLE rignal Filed May 24, 1963 y frzvefz fr EdzacZ/dJjz/coqfa N Nwwnm United States Patent O May 24, No. 449,364

This application is a continuation of application Ser. No. 282,934, led May 24, 1963, now abandoned, and assigned to the assignee of the present application.

This invention relates to an improved fuel injection nozzle for use in an internal combustion engine and more particularly to a fuel injection nozzle for use in direct cylinder injection.

One of the problems encountered in the past in direct cylinder injection as distinguished from manifold injection is that there is a greater tendency in the former environment for carbon deposits to form on the nozzle tip. This contributes to greater valve wear and progressive decreasing of the efficiency of the nozzle in spraying fuel into the fuel cylinder.

Accordingly, a principal object of this invention is to provide a structure particularly useful in direct cylinder injection constructed in a manner to minimize carbon deposits on the nozzle tip.

Another object is to provide a nozzle tip formed with a knife-like edge to preserve the efiiciency of the fuel injection nozzle by minimizing the surface available for carbon deposits to accumulate.

Other and more particular objects, advantages, and uses of my invention will become apparent from a reading of the following specification taken in conjunction with the accompanying drawings which forms a part thereof and wherein:

FIGURE 1 is a longitudinal sectional view of the improved fuel injection nozzle of the present invention;

FIGURE 2 is an enlarged view of a portion of the nozzle tip shown in relation to the nozzle body member and the valve member;

FIGURE 3 is an illustration of the nozzle of FIGURE 1 as it is positioned in a cylinder head of an internal combustion engine.

Like characters of reference designate like parts in the several views.

Referring now to FIGURE l the illustrated nozzle comprises an elongated tube-like nozzle body 12, a nozzle tip 14, a valve member or pintle 16, a spring 18, a spring retainer member 20, and a filter 22.

The body member 12 is formed with a longitudinal bore 24 providing a fuel passage therethrough. The filter 22 is positioned at the inlet end of the bore 24. The nozzle body member is also formed With a cylindrical bore 26 opposite the inlet end, the bore 26 being an enlarged extension of a portion of bore 24 adapted to receive the nozzle tip 14. The nozzle body 12 is threaded at 27 for insertion into the cylinder block C as shown in FIGURE 3, and is formed with a skirt portion 28 which extends over a portion of the outer end of the nozzle tip the purpose of which is hereinafter further explained.

The nozzle tip 14 comprises a first portion 30 and a second portion 32. The first portion 30 is adapted to be press fitted into the cylindrical bore 26 of the nozzle body. The first and second portions 30 and 32 are separated by circumferential groove 34. The purpose of the groove 34 is hereinafter more fully explained. The nozzle tip 14 is formed with a longitudinally extending cylindrical bore 36 defining a fuel passage therethrough which is in communication With the bore 24. At the outer end of the bore 36 there is formed a truste-conical opening defining a valve seat surface 38 for the valve member 16. The end of the nozzle tip is chamfered at 40 so that ice a knife edge 42 is formed by the intersection of the valve seat surface 38 and the chamfer 40. The purpose of this knife edge will be hereinafter more clearly explained. The second portion of the nozzle tip 14 is of a smaller diameter than the bore 26 to provide a radial clearance 44 between the skirt portion 28 of the bore 26 and the second portion 32. Depending on certain conditions of cylinder design the distance the nozzle t-ip protrudes into the cylinder is of critical importance to obtain optimum efficiency of the combustible mixture in the cylinder. In certain instances a relatively short protrusion of the nozzle tip into the cylinder is required. Under those conditions the threaded skirt portion 28 must extend well toward the end of the nozzle tip as shown in FIGURE 1. It is then that it becomes necessary to have the clearance 44 between the inner periphery of the skirt 28 defined by the extension of bore 26 and the outer periphery of the second portion 32 of the nozzle tip.

The valve member or pintle 16 comprises a valve stem 46 and an enlarged substantially hemispherical head 48 formed on one end thereof. The head 48 is adapted to be seated on the valve seat surface 38. The head 48 is of such a size that in a seated position the outer face 49 of the head 48 is almost flush with the surrounding knife edge 42. The valve member is held in. a `seated position by means of the spring 18 surrounding the valve stern 46, the spring being seated at one end in a recess 50 formed on the inner end of the first portion 30 of the nozzle tip 14 and at the other end against the retainer 20. This assembly of the nozzle tip, spring, valve member and spring retainer is `similar to that disclosed in copending application, Ser. No. 248,551, led Dec. 31, 1962.

A suitable filter 22 is disposed in the longitudinal passage 24 to filter fuel before it is injected into the engine through the nozzle tip 14.

The purpose of the knife edge 42 is to minimize the surface available on the nozzle tip 14 for accumulation of carbon deposits. Carbon `deposits will tend to form on a nozzle tip when it is positioned in direct communication with cylinder of the internal combustion engine as shown in FIGURE 3. These carbon deposits result from un-burned fuel. If a substantial surface is available these deposits tend to be rather substantial and will tend to clog up the end of the nozzle tip. This contributes to the wear of the valve head and the nozzle tip and brings about uneven fuel spray patterns, thereby reducing the efiiciency of the nozzle. Accordingly, I have reduced the surface available for the formation of these carbon deposits by providing on the nozzle t-ip end a knife edge 42, which, as shown in this preferred embodiment, can be easily formed by providing a chamfer 40 which will intersect the valve seat surface 38. Thus in conjunction with the knife edge 42 the wash of fuel flowing through the passages 24 and 36 further reduces the tendency for formation of carbon deposits.

It will be noted that I have provided a radial clearance 44 between the second portion 32 of the nozzle tip and the cylindrical bore 26. This has been done in order to avoid the necessity of press fitting the second portion 32 of the nozzle tip into the cylindrical bore 26 which would tend to set up stresses which could be transmitted to the valve seat surface 38. The circumferential groove 34 is also a stress relieving feature which prevents stresses set up when the first portion 30 is press fitted into bore 26 from being transmitted to the valve seat 38.

Thus there are provided in my nozzle tip the combination of two features to serve a stress relieving function. These stress relieving features are the circumferential groove 34 and the clearance 44 between the cylindrical bore 26 and the second portion 32 of the nozzle tip 14.

Thus provision of stress relieving features to prevent distortion of the valve seat surface 38 and provision of the knife edge 42 on the nozzle tip 14 to prevent accumulation of carbon deposits both contribute to a more effective valve seating arrangement by minimizing distortion within the tip itself and clogging of the tip from an outside source, namely, un-burned carbons Within the cylinder.

While I have `shown and described a certain specific structure as comprising a preferred embodiment of my invention it is to be understood that this is by Way of example and that my invention is to be defined by the appended claim.

I claim:

A fuel injection nozzle comprising, an elongated body 'member having a longitudinal passage extending therethrough including an enlarged generally cylindrical bore,

"a nozzle tip secured to saidV body member having a longitudinal passage extending therethrough, said passage in said tip including a generally cylindrical portion in communication with said passage of said body member and a generally frusto-conical portion diverging from said cylindrical portion and terminating in an enlarged outer open end, said tip including a first portion `surrounding a portion of said cylindrical portion of said passage and a second portion surrounding said conical portion thereof, said first portion of said tip including a generally cylindrical outer surface press lit into said enlarged generally cylindrical bore of said body member and said second portion being disposed substantially Within said 30 enlarged cylindrical bore and including a generally cylindrical outer surface spaced from said bore to define an annular space therebetween, said first and second portions of said tip being connected by a reduced portion defining an annular open groove intermediate said portions eifective to reduce the transmission of `stresses from said first portion to said second portion, said tip further including an external generally conical chamfered portion joining in an acute angle With said conical portion of said passage at said outer open end to define a knife edge therearound, and said nozzle further including a movable valve member disposed Within said passage within said tip having an enlarged generally hemispherical head portion disposed entirely Within said conical portion of said passage, said head portion being urged into sealing engagement with said conical portion of said passage internally of said knife edge and said head including an outer end disposed approximately flush with said knife edge when said head and said conical portion of said passage are in said sealing engagement.

References Cited UNITED STATES PATENTS 1,206,359 1l/l9l6- Ohlsson 239-453 1,225,703 5/1917 Davol 239-88 2,096,581 10/1937 Goldberg 239-453 2,874,000 2/1959 Nystrom 239-453 2,975,982 3/1961 Dahl 239-453 FOREIGN PATENTS 928,499 6/ 1955 Germany.

EVERETT W. KIRBY, Primary Examiner. 

